KF drive cores

[Starfox1701]

Ok been doing research in kf drives and have a question, why is germanium used in nd drives? As superconductors go these days its rather meh and was not a top tier superconductor in 86 when the jumpships where first getting fleshed out. What are the specific properties of this material in universe that make it the sole choice for kf drives? Based on drive description any superconducting capacitor should be able to do the job as the hyperspace field is generated in another component. So what's the 411?

[cray]

As superconductors go these days its rather meh and was not a top tier superconductor in 86 when the jumpships where first getting fleshed out.

All true.

What are the specific properties of this material in universe that make it the sole choice for kf drives?

It isn't the sole choice. Drive cores actually also contain titanium, as suggested in sources as old as DropShips & JumpShips and as recent as Strategic Operationans. Per the description of sub-compact drive cores in Tactical Operations, the ratio of titanium and germanium varies by drive design (sub-compact, compact, standard).

Of course, a quick check on titanium will show it's not a wondrous superconductor, either, and any titanium-germanium compound or alloy is either poorly described in literature or has unimpressive properties.

Based on drive description any superconducting capacitor should be able to do the job as the hyperspace field is generated in another component. So what's the 411?

The core is not just a superconducting capacitor. As indicated at some length in Aerotech 2 revised and especially Strategic Operations, the core is a critical "antenna" for shaping the hyperspace field that comes from the initiator. Similarly, it's integration with docking collars and the KF booms of DropShips is critical for carrying DropShips through a jump. Meanwhile, its energy storage capabilities can be replicated by the much smaller, very different lithium-fusion battery.

So, point 1: the superconducting properties of the material are probably secondary since, as you noted, germanium (and titanium) aren't great superconductors.

Point 2: the properties of the titanium-germanium mixture (compound? alloy? your guess is as good as mine) have more to do with the ill-described hyperspace functions of the KF drive than energy storage.

[Starfox1701]

Actually the Revised Aerotech2 book specifies that it is the superconducting property of the core that boots and expands the field. Based on the comparison of each description from the various sourcebooks I've read so far the superconductivity spears to be key not the specific material.  Gremanium spears to have been chosen from a game design point of view purely for its apparent rarity here on earth at 1.6 ppm in the crust. If material is irrelevant and superconductivity is the defining factor then theoretically and sufficiently strong superconducting material could be used as long as it can stand up to the physical stresses of both being the keel of the vessel and the operational strain of discharging its accumulated capacitance load and then receiving and redirecting the energies of the incoming hyperspace field energies within seconds of each other.

Besides the cost of transit drives of core construction is the defining cost factor for ftl space craft. Having other materials options that are more cost effective as well as differing in weight constraints would have a radical effect on the jumpships industry. It might also finally allow for the 30ly limit to be broken. At present I can find no definitive reason why such advancements can't occur within the game universe other then the running gag of "we never thought of that" which has applied to so many things in universe over the years. What I'm looking for is a hard reason why jump cores have to be made from titanium and germanium as opposed to nobium and titanium or pressurised hydrogen sulfide?

[cray]

Actually the Revised Aerotech2 book specifies that it is the superconducting property of the core that boots and expands the field. Based on the comparison of each description from the various sourcebooks I've read so far the superconductivity spears to be key not the specific material.

If it was only about superconductivity, then the KF drives wouldn't use bad superconductors like titanium-germanium mixes. I would've been happy to write in something like magnesium diboride or mercury barium calcium copper oxide for the sub-compact drive if there was room for an alternative to titanium-germanium. But the function of the core as a "hyperspace antenna" (StratOps p. 123) is the other key aspect.

It's worth noting the p. 130 StratOps discussion of salvaging JumpShips. The titanium-germanium core of ships interacts with hyperspace fields even when it's disabled and non-superconducting.

"The only other way to transport a K-F core is to fragment it down to gravel and, preferably, chemically process the titanium-germanium material into something less likely to interfere with a hyperspace field."

Superconductors found throughout fusion engines and in 31st Century electrical systems do not impact hyperspace fields the way titanium-germanium does.

If material is irrelevant and superconductivity is the defining factor

Superconducting isn't the defining factor, or much more common, convenient superconducting materials would be used. Magnesium diboride, for example, would be fun - it could use liquid hydrogen coolant (with significant margin), it's quite durable, and the elements are relatively common.

What I'm looking for is a hard reason why jump cores have to be made from titanium and germanium as opposed to nobium and titanium or pressurised hydrogen sulfide?

Titanium-germanium has that magical reaction with hyperspace fields, to the point it's preferable to chemically modify it when a salvage ship is trying to jump a wrecked KF core.

[Starfox1701]

But no one knows how that magical reaction works? :( I mean I wasn't looking for the whole codex of research from the Deimos project but I was hoping for a few technical details. Maybe they will let you guys do that as part of another retotech tro. If there's any information I've missed I'd appreciate a point in that direction other wise thanks for your help.

[cray]

But no one knows how that magical reaction works? :(

Germanium was selected during the beer-n-pretzels phase of BattleTech's creation. I might be able to pass along a question to the original writers, but I think just about everything made it into the books, especially DropShips & JumpShips. What I've been able to write into TacOps and Strategic Operations is the most detail yet.

If there's any information I've missed I'd appreciate a point in that direction other wise thanks for your help.

Off the top of my head, the main books with KF drive operational data are:

DropShips & JumpShips
BattleSpace
Explorer Corps
Aerotech 2 Revised
Tactical Operations
Strategic Operations

Strategic Operations tries to summarize KF drives data found in DS&JS, BattleSpace, Explorer Corps, and AT2R, and adds quite a few new details. Do you have Strategic Operations? I don't want to summarize two chapters if you have the book. ;)

I mean I wasn't looking for the whole codex of research from the Deimos project but I was hoping for a few technical details. Maybe they will let you guys do that as part of another retotech tro.

It's not a matter of letting, but rather an issue of how much verifiable detail you want to put into a fictional, magical technology. The more detail that goes in, the more loopholes open up and the more flaws become apparent. KF drives are at a point where they work in game rules, and work fairly consistently in fiction. For example, there are no arguments over differing warp speed scales to trip up authors. And there are no inconvenient real world gravity telescopes undermining hyperspace travel, the way a lot of the Honorverse FTL just got kicked in the tenders by the confirmation that gravity travels (very boringly) at light speed.

A fair portion of Strategic Operations' discussion on KF drives is about addressing questions raised by increasing detail available on KF drives. How "pigeons" are possible without KF cores; how KF drives can match the movement of target stars, but can't emerge with some relative velocity; which Lagrange points are viable jump points without violating prior rules of hyperspace travel; how recovering stranded JumpShips can be done; why mobile shipyards can't jump with JumpShips on board; etc.

Look at our discussion here: based on prior references about superconducting aspects of KF cores, you're looking at alternatives to germanium to change a fundamental aspect of KF cores. (For one thousand years, only titanium-germanium mixes have been used in cores despite endless research efforts). Others have observed that the precisely defined solar sails of KF drives don't really soak up that much energy - I once calculated you could recharge a typical drive with a few hundred tons of diesel and oxygen, so sails or the high hydrogen consumption of fusion charging doesn't make sense. It's also fun to try to show how a JumpShip with lots of docking collars can send signals a few minutes into the past.

Kearny-Fuchida drives are in a good place where their behavior is predictable, where they're usable in fiction and games, and some technobabble is available to help fill in the background. Giving even more detail to something that works for fundamentally fictional, hard-to-justify reasons doesn't necessarily help. It'd be too easy to write in something that felt clever about KF cores now (e.g., "the unique hexavalent configuration of titanium-germanium is required to shape hyperspace fields"), only to watch it undermine staples of their operation later (e.g., someone points out a dozen elements with hexavalent states).

[Starfox1701]

I have all those books but have yet to get through explorer corps though I did start it. As far as for reasons you could always barrow from star trek and go dilithium on it and give it an extradimentional structural componet. I mean it would track well with some of the things alluded too in the SO article. And its not something likely to be undermined by physics anytime soon. Besides germanium is made in nearly dead stars at the absolute end of there lifecycle just before supernova. That's bound to end up giving it some hinky quantum thing in a radioactive spider sort of way. Look HPGs and KF drive are realisticly the only magufin tech in the whole universe. Sure some of the other stuff might not make sense based on what we know right now or what we can do, lrms I'm looking at you, but its not whole cloth imaginary either.

I understand what your saying and it can be a delicate road when your world building. In sci-fi there definitely is such a thing as too much information. I don't like not knowing but I accept that I don't absolutely need to know, I just want to know. It would be nice but not if it breaks the universe.

 Your right when you say I was looking for other materials for cores and I figured I had a 50/50 chance of not getting shot down. I didn't get what I wanted but the SO article does leave some wiggle room for innovation and the subcompact kf drive indicates that titanium is a noncritical component for the jump part of the core but instead seams to be present for structural reasons in the alloy so there's that.     

[cray]

I didn't get what I wanted but the SO article does leave some wiggle room for innovation and the subcompact kf drive indicates that titanium is a noncritical component for the jump part of the core but instead seams to be present for structural reasons in the alloy so there's that.   

My intent was to imply there's something about the ratio of titanium and germanium that influences hyperspace field performance in drives. As suggested in the minuscule word count available in TacOps p. 344, "common wisdom" among hyperspace drive engineers would be that smaller drives, like those of WarShips and sub-compact cores, have a higher titanium ratio. The actual sub-compact core is nearly titanium-free, which is "counter-intuitive" to Inner Sphere drive designers.

I had to cut a lot of my draft out of that entry. We had about 100 words of fluff per TacOps item of equipment.

[Starfox1701]

Well that makes a certain amount of sense but at least in my case that compact cores have higher ratio of titanium is not my goto leap of logic here because as far as I can recall there isn't any mention anywhere of different core types having different titanium and germanium ratios. The Primative KF drive entry that should have been in Interstellar Operations would have been a good place for that info drop as its most pertinent to early drive development and refinement

[cray]

The Primative KF drive entry that should have been in Interstellar Operations would have been a good place for that info drop as its most pertinent to early drive development and refinement

That primitive KF drives would be covered in Interstellar Operations wasn't known when I had a chance to write up subcompact drives in TacOps - the books are separated by years. You take the opportunities as presented.

[Starfox1701]

That I understand. But my other point remains there should be a fluff entry in IO and there's not. Just construction rules unless I missed something again.

[Starfox1701]

Ok I've got another question and I'm not sure how to phrase it. So here's a bit of setup

 While reading through TM about Dropships it stats the following about dropship size, that you might as well put a jump core in anything bigger than 100000 tons because the cost of a kf boom is so high its almost cheper to mount a full drive instead.  Then in SO there the fact that for some reason adding docking collars increases the cost of the KF drive but it really doesn't explain why it specifically increases the cost of the drive not the ship.

Ok so can somebody sort this out for me? I understand we are dancing around the need to know line again. First TM specifically states that kf booms are a dropship component. I was under the impression from earlier books that kf booms were part of docking collars and that it was collar space limitations that limited dropship size, not the cost of a component that we don't even mount during construction. Ok putting aside the obvious construction implications for dropships there some serious cost issues with kf booms and docking collars that implies some kind of parts commonality with jump drives that's not specifically stated in the lore. So what gives? If the boom is on the droper then why are collars ungodly expensive and just how big are these booms anyway and what are they made of that they cost almost as much as a jump drive but don't take up any space on a dropship?

[cray]

Ok so can somebody sort this out for me? I understand we are dancing around the need to know line again.

There's not a secret about it. It's just that there's a hard rules limit of 100,000 tons per collar. [insert fluff to explain]

that it was collar space limitations that limited dropship size, not the cost of a component that we don't even mount during construction.

Nope, collar space limitations are a secondary the issue. After all, a single collar ship like the Scout has all the room in the universe to carry a DropShip. Why not go to 1 million or 10 million tons per collar when you have all that room? Because the rules were set at 100,000 tons to keep DropShips from getting bigger than WarShips and JumpShips.

So what gives? If the boom is on the droper

There's no "if." KF Booms were stated as being part of DropShips in the 1988 publication, "DropShips & JumpShips." Subsequent publications have repeated the description and function of KF booms.

then why are collars ungodly expensive

The KF boom doesn't work without a jump drive. The "docking collar" on the JumpShip is an integral part of the JumpShip's KF drive and a hideously complicated piece of machinery meant to carry a DropShip through hyperspace, very different from other docking sites - per StratOps, you can dock at any cargo bay door. But only KF drives' docking collars will carry you through hyperspace. Matching hardware is required in the DropShip, the KF boom, to properly map the mass inside the DropShip.

Without the boom, the KF drive is as blind to the DropShip as it is to someone sitting on the hull of the JumpShip or a nearby aerospace fighter. See StratOps, BattleSpace, and AT2R for the damage inflicted on objects near a JumpShip but not safely integrated into a jump drive by a boom.

and just how big are these booms anyway

They're an integral part of the DropShip's structure, controls, and other vital systems, so they don't have a separate mass. KF booms have an obvious price impact, though. Compare the cost multiplier of DropShips to small craft and space stations.

and what are they made of that they cost almost as much as a jump drive

The material requirements of the KF boom haven't been explicitly stated.

but don't take up any space on a dropship?

Why do you say they don't take up space on a DropShip?

[Starfox1701]

Why do you say they don't take up space on a DropShip?

Because its never explained that ther are part of the ships internal structure and its constantly implied to be a totally separate piece of equipment, one that we don't mount during the construction process.

As far as dropship size goes this isn't about building bigger dropers. Its about understanding why the boom is so expensive that at around 100000 tons mounting a jump drive becomes a cheaper alternative. The cost is the in universe reason given and I know about the hardline on the rules I was just wondering. If there was any underling logic to back stop the in universe reason.

[cray]

If there was any underling logic to back stop the in universe reason.

The idea of the KF boom getting as expensive and complicated as a full KF core was a line quickly tossed in to a) explain why DropShips had such incredible cost multipliers, a factor that generated some player consternation prior to the publication of the new core books; and b) help explain the 100,000-ton limit.

At the time this explanation was added, the KF boom had already been in the game (DropShips & JumpShips) and even on critical hit tables (at least AT2 if not earlier). The KF boom was the differentiating factor between DropShips and craft with similar all-environment capabilities (fighters, smallcraft), and craft of similar tonnage and strategic fuel mode but no KF core (space stations). Based on this, the unpublished rules for jump-capable stations (stations that could be carried on KF drives' collars) would include a much higher cost multiplier, too.

So, the boom was handy to explain a lot of things. That it lacked it's own, differentiated mass didn't seem to matter. After all, it was on DropShip crit tables as identifiable hardware and there was plenty of mass in DropShips' structure, drive, and controls to cover the boom, much in the same way most of the mass for grav decks is contained in a vessel's structure and crew quarters mass.

[Starfox1701]

This makes a certain amount of since from a game design perspective. You would only need to revisit the differentiated mass issue if you added true parasite warships to the game. Say something in the 240k to 300k range. Since that design quirk for collars means a 300k ship would need 5 collars very few cannon ships could carry anything that big meaning there would already be another size break in place already.